New reactive core WIP

src/Library/DeclarativeProperty/DeclarativePropertyExtensions.cs

@@ -0,0 +1,63 @@
+using System.Collections.ObjectModel;
+using System.Collections.Specialized;
+using ObservableComputations;
+
+namespace DeclarativeProperty;
+
+public static class DeclarativePropertyExtensions
+{
+    public static IDeclarativeProperty<T> Debounce<T>(this IDeclarativeProperty<T> from, TimeSpan interval, bool resetTimer = false)
+        => new DebounceProperty<T>(from, interval){ResetTimer = resetTimer};
+
+    public static IDeclarativeProperty<T> DistinctUntilChanged<T>(this IDeclarativeProperty<T> from)
+        => new DistinctUntilChangedProperty<T>(from);
+
+    public static IDeclarativeProperty<TTo?> Map<TFrom, TTo>(this IDeclarativeProperty<TFrom?> from, Func<TFrom?, CancellationToken, Task<TTo?>> mapper)
+        => new MapProperty<TFrom?, TTo?>(mapper, from);
+
+    public static IDeclarativeProperty<TTo?> Map<TFrom, TTo>(this IDeclarativeProperty<TFrom?> from, Func<TFrom?, TTo?> mapper)
+        => new MapProperty<TFrom?, TTo?>((next, _) => Task.FromResult(mapper(next)), from);
+
+    public static async Task<IDeclarativeProperty<TTo?>> MapAsync<TFrom, TTo>(this IDeclarativeProperty<TFrom?> from, Func<TFrom?, CancellationToken, Task<TTo?>> mapper)
+        => await MapProperty<TFrom?, TTo?>.CreateAsync(mapper, from);
+
+    public static async Task<IDeclarativeProperty<TTo?>> MapAsync<TFrom, TTo>(this IDeclarativeProperty<TFrom?> from, Func<TFrom?, TTo?> mapper)
+        => await MapProperty<TFrom?, TTo?>.CreateAsync((next, _) => Task.FromResult(mapper(next)), from);
+
+    public static IDisposable Subscribe<T>(this IDeclarativeProperty<T> property, Action<T?, CancellationToken> onChange)
+        => property.Subscribe((value, token) =>
+        {
+            onChange(value, token);
+            return Task.CompletedTask;
+        });
+
+    public static IDisposable Subscribe<T>(this IDeclarativeProperty<T> property, Action<T?> onChange)
+        => property.Subscribe((value, _) =>
+        {
+            onChange(value);
+            return Task.CompletedTask;
+        });
+
+    public static IDeclarativeProperty<T> Extract<T>(
+        this IDeclarativeProperty<ReadOnlyObservableCollection<T>> from,
+        Func<IList<T>?, T?> extractor
+    )
+        => new ExtractorProperty<T>(from, extractor);
+
+    public static IDeclarativeProperty<T> Extract<T>(
+        this IDeclarativeProperty<ObservableCollection<T>> from,
+        Func<IList<T>?, T?> extractor
+    )
+        => new ExtractorProperty<T>(from, extractor);
+
+    public static IDeclarativeProperty<T> Extract<T>(
+        this IDeclarativeProperty<CollectionComputing<T>> from,
+        Func<IList<T>?, T?> extractor
+    )
+        => new ExtractorProperty<T>(from, extractor);
+
+    public static IDeclarativeProperty<TCollection?> Watch<TCollection, TItem>(
+        this IDeclarativeProperty<TCollection?> collection)
+        where TCollection : IList<TItem>, INotifyCollectionChanged
+        => new CollectionRepeaterProperty<TCollection?, TItem>(collection);
+}